Acute anxiety and autonomic arousal induced by CO2 inhalation impairs prefrontal executive functions in healthy humans

Abstract

Acute anxiety impacts cognitive performance. Inhalation of air enriched with carbon dioxide (CO2) in healthy humans provides a novel experimental model of generalised anxiety, but has not previously been used to assess cognition. We used inhalation of 7.5% CO2 to induce acute anxiety and autonomic arousal in healthy volunteers during neuropsychological tasks of cognitive flexibility, emotional processing and spatial working memory in a single-blind, placebo-controlled, randomized, crossover, within-subjects study. In Experiment 1 (n = 44), participants made significantly more extra-dimensional shift errors on the Cambridge Neuropsychological Test Automated Battery (CANTAB) Intra-Extra Dimensional Set Shift task under CO2 inhalation compared with ‘normal’ air. Participants also had slower latencies when responding to positive words and made significantly more omission errors for negative words on the CANTAB Affective Go/No-go task. In Experiment 2 (n = 28), participants made significantly more total errors and had poorer heuristic search strategy on the CANTAB Spatial Working Memory task. In both experiments, CO2 inhalation significantly increased negative affect; state anxiety and fear; symptoms of panic; and systolic blood pressure/heart rate. Overall, CO2 inhalation produced robust anxiogenic effects and impaired fronto-executive functions of cognitive flexibility and working memory. Effects on emotional processing suggested a mood-congruent slowing in processing speed in the absence of a negative attentional bias. State-dependent effects of anxiety on cognitive-emotional interactions in the prefrontal cortex warrant further investigation.

Arabic version of the Hayling sentence completion test: scale validation, normative data and factors associated with executive functions in a sample of the Lebanese adults

“…However, indoor air pollution attributed to the use of wood burning as a heating system is linked to a lower performance of the interviewed participants, particularly in the number of errors committed in the inhibition condition of the A-HSCT. This negative correlation could be due to the exposure of individuals to air pollutants resulting from wood burning chemical reactions, as mentioned in various studies, particularly CO2 inhalation that is anxiogenic and deleterious for executive functions [41,42]. In contrast, participants who use electricity as a source of heating in their households performed better in terms of response-time in the inhibition condition of our test, which goes in line with the result mentioned above.…”

The effects of carbon dioxide exposure concentrations on human vigilance and sentiment in an enclosed workplace environment

“…Similarly, Snow et al 25 also reported no significant differences between 800 and 2700 ppm CO 2 exposures for both positive affect score and negative affect score. But, the significant effects of CO 2 exposure on human sentiment have been observed when participants inhaled air enriched with 7.5% CO 2 , and they showed a decrease in positive affect and an increase in negative affect 28,29 …”

“…Snow et al 25 investigated the effects of CO 2 concentration on human sentiment using the Positive and Negative Affect Schedule (PANAS), and their findings suggested no significant differences between 800 and 2700 ppm CO 2 exposures for both positive affect and negative affect. Savulich et al 28 reported that the negative affect increased when participants inhaled the air enriched with 7.5% CO 2 . Further, Attwood et al 29 observed not only an increase in negative affect, but also a decrease in positive affect.…”

Arabic version of the Hayling sentence completion test: Validation and factors associated with executive functions in a sample of the Lebanese adults

“…However, indoor air pollution attributed to the use of wood burning as a heating system is linked to a lower performance of the interviewed participants, particularly in the number of errors commited in the inhibition condition of the A-HSCT. This negative correlation could be due to the exposure of individuals to air pollutants resulting from wood burning chemical reactions, as mentioned in various studies, particularly CO2 inhalation that is anxiogenic and deleterious for executive functions 41,42 . In contrast, participants who use electricity as a source of heating in their households performed better in terms of response-time in the inhibition condition of our test, which goes in line with the result mentioned above.…”